Grandmother on my father's side

I am looking for information on grandmother on my father's side.I have no information.My father Donald McGowen lives in Houston, Texas and was born in February of 1935. Rumor has it that his mother was from Smithville, Texas and was incarerated in an asylum when he was young (and his mother was quite young).Obviously I have my work cut out for me.This is all the information I have and my father isn't talking.